Thermostat



June 19, 1923. 1,458,924

H. F. BANAN THERMOSTA'I Filed Jan. 20 1920 flmss [r/wv Brass fromINVENTOR 4M BY Patented June 19, 1923.

UNITED STATES PATENT OFFICE.

HORACE I. BANAN, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOB 1'0 WESTINGHOUSEELECTRIC & IANUFACTUBING COMPANY, A CORPORATION OF PENNSYLVANIA.

THERIOSTAT.

Application filed January 20, 1920. Serial No. 352,891.

To allwkomitma concern:

Be it known t at I, Honacn F. BANAN,

a citizen of the United States, and a resident of Wilkinsburg, in thecounty of Alle 6 gheny and State of Pennsylvania, have invented a newand useful Improvement in Thermostats, of which the following is .aspecification. My invention relates to thermostats and articularly tothermostats of the bi-metalie type.

One object of my invention is to provide a thermostat whereby thetemperature of a heat-sbora e device may be controlled between preetermined desirable limits.

-Another object of my invention is to provide a device of the aboveindicated char acter that shall be simple and compact in constructionand positive and reliable in operation.

In practising my invention, I provide two helical bismetallic membersthat are secured to a stationary member at one end thereof and adaptedto actuate a buckling spring at the other end thereof. The bimetallicmembers are so disposed that they tend to turn in opposite directionsand actuate the buckling spring, when subjected to temperature changes.The buckling spring actuates a resilient pivotally mounted member toe'fiect engagement between a movable contact member and a plurality ofstationary contact members. A magnetic member is provided to maintainpositive engagement between the movable and the stationary contactmembers that are engaged while the heating element of a heat-storagedevice, that is controlled by the thermostat is energized. The magneticmember also 60 causes disengagement'of the contact members to beeffected with a snap action. Where a comparatively lar current isdesired for energizing the heating element of a heatstorage device thethermostat embodying in invention may be used to so actuate a relay thatit may close andopen the circuit of the heating element.

In the accompanying dram'ngs, Fig. 1 is a plan view, partially. insection, of'the device embodying my invention; Fig. 2 is a frontelevational view of the device shown in Fig. 1; Fig; 3 is a diagrammaticview of a temperature-control circuit embodying the device shown in Fig.1; Fig. 4 is a diagrammatic view of a modified form oftemperature-control circuit embodying the device shown in Fig. 1.

A thermostat 1 for controlling the temperature of a heat-storage device2 comprises a plurality of helical bi-metallic members 3 and 4 in acasing 5 that is adapted to be inserted in the heat-storage device 2.The bi-metallic members 3 and 4 are secured to the casing 5 at one endthereof and are adapted to actuate a plurality of cam members 6 and 7 bythe other ends thereof. A buckling spring 8 is so disposed between thecam members 6 and 7 as to be buckled thereby upon the occurrence of apredetermined temperature in the heatstorage device 2. The bimetallicmember 3 is so wound that the element having the greater coefiicient ofexpansion is disposed within the helix and the member 4 is so wound thatthe corresponding element is disposed on the outer side of the helix.Upon an increase in the ambient temperature, the two members tend,therefore, to turn in opposite directions, because of the differentialdisposition of the elements composing the same. A compression force isthus applied to the ends of the spring 8. by means of the cam members 6and 7, that causes the spring to buckle.

A resilient member 9 is'pivotally mounted, at one end thereof. on aterminal 10 and has a contact member 11 mounted on the other endthereof. A plurality of terminal blocks 12 and 13 have a plurality ofcontact members 14 and 15 respectively secured thereto and are sodisposed. at the respective sides of the free end of the resilientmember 9. that engagement is efiected between the stationary contactmembers 14 and 15 and the movable contact member 11 when the resilientmember 9 is actuated by the buckling spring 8. In a simple form of thedevice in which engagement and discengagement only. between the contactmembers, are desired, a magnetic member 16 .is provided to so attracttheresilient mem-' her 9 thereto as to maintain positive eng gementbetween the contact members 11 a d 14 until the. disengagement thereof.The magnetic member 16 further serves to cause the disengagement of thecontact members 11 and 14 to e eflected with a snap action.

In a simple control circuit, the latter form of controlling device isemployed, as lllllS- trated in Fig. 3 of the accompanying drawings. Aheating element 17 1s adapted to heat the storage device 2 and isconnected in series with the circuit 18 and the thermostat device 1. Aconductor 18a, of the circult 18, is connected to the terminal block 10of the thermostat 1, and a conductor 18?) is connected to one terminalof the heating element 17 the other terminal of which is connected tothe terminal block 12.

In the circuit that is illustrated in Fig. 4, a change-over relay 19 isemployed. The relay 19 comprises a plurality of contact members 20 and21 and a plurality of energizing windings 22 and 23, respectively. ()neterminal of each winding 22 and 23 is connected to the terminal blocks13 and 12, respectively, and the other terminal of each winding 22 and23 is connected to the opposite contact members 21 and 20, respectively.The movable contactmember 24 is so mounted as to be actuated by thewindings 22 and 23 to offeet engagement with the stationary contactmembers 20 and 21. The heating element 17 of the storage device 2 isconnected between the contact member 21 of the relay 19 and the terminalblock 10 of the thermostat 1. One conductor 18a of the circuit 18 isconnected to the terminal block 10 and the other conductor 18?) isconnected to the movable contact member 24 of the relay 19.

As the temperature of the heat-storage device 2 attains a predeterminedvalue; the bimetallic members 3 and 4 so turn the cam members 6 and 7 asto produce a buckling effect in the spring 8 therebetween, that causesit to actuate the pivotally-mounted member 9. In the circuit that isillustrated in Fig. 3, the disengagement of thescontact members 11 and14 opens the circuit of the heating element 17 and precludes a currentfrom traversing the same until the temperature in the heat-storagedevice 2 has been so reduced that the bi-metallic members 3 and 4 assumetheir initial positions. In the circuit that is illustrated in Fig. 4,actuation of the resilient member 9 efi'ects disengagement of thecontact members 11 and 14, and engagement between the contact members 11and 15. A circuit is thereby completed from the conductor 18a, throughthe resilient member 9, the contacts 11 and 15, the winding 22 and thecontacts 21 and 24 of the relay 19, to the conductor 186, that energizesthe winding 22. The winding 22, having become thus energized, soactuates the contact member 24 as to effect disengagement of the contactmembers 21 and 24 and engagement between the. ccitact members 20 and 24.The disengagement of the contact members 21 and 24 interrupts the flowof current through the heating element 17. After the temperature hasbeen sufiiciently reduced in the heat-storage device 2, the bimetallicmembers 3 and 4 assume their initial positions and permit the bucklingspring 8 to assume its initial position. The resilient member 9 is,consequently, permitted to return to its initial position, therebyeffecting disengagement of the contact members 11 and 15 and engagementof the contact members 11 and 14. A circuit for energizing the winding23 is thereby completed from the conductor 18a, through the resilientmember 9, the contact members 11 and 14, the winding 23 and the contactmembers 20 and 24, to the conductor 18?). The winding 23, beingenergized so actuates the contact member 24 as to effect disengagementof the contact members 20 and 24 and engagement between the contactmembers 21 and 24. The circuit connections for energizing the heatingelement 17 of the heat-storage device 2 is thereby recompleted from theconductor 18a, through the heating element 17 and the contact members 21and 24, to the conductor 18b.

Although I have shown'a plurality of devices embodying my invention, itis not limited to the particular construction shown since variousmodifications may be made therein without departing from the spirit andscope of the invention as set forth in the appended claims.

I claim as my invention:

1. In a thermostat, the combination with a resilient member and aplurality of contact members, engagement of which is effeoted by theresilient member, of a plurality of differentially-wound helicalbi-metallic members for actuating the resilient member.

2. In a thermostat, the combination with a plurality of resilientmembers and a plu- I rality of contact members, engagement of which isefi'ected'by the resilient members, of a plurality of helicalbi-metallic members "mechanically co-operating to actuate the resilientmembers. I

3. In a. thermostat, the combination with a plurality of resilientmembers, a plurality of stationary contact members and a movable contactmember actuated by the resilient members, of a plurality of helicalbi-metal- Lie members for actuating the resilient mem- 4. In a.thermostat, the combination with a plurality of cam members, a pluralityof resilient members actuated by the cam members and a plurality ofcontact members, engagement of which is effected by the resilientmembers, of a plurality-off-helical bimetallic members for actuating thecam members.

5. In a thermostat, the combination with a plurality of cam members, abuckling member actuated thereby, a plurality of contact members and aresilient member for effect ing engagement thereof in accordance withthe movement of the buckling member, of a plurality of helicalbi-metallic members for actuating the cam members.

6. In a thermostat, the combination with a lurality of contact membersand a movab e contact member adapted to efiect engagement therewith, ofa plurality of hellcal bi-metallic members, a plurality of cam membersactuated thereby, and a buckling member so actuated by the cam membersas to effect engagement between the stationary and the movable'contactmembers in accor ance with the movement thereof.

7. In a thermostat, the combination with a plurality of contact membersand means for causing the disengagement, thereof to be effected with asnap actlon, of a plurality of helical bi-metallic members a casingtherefor, a plurality of cam members actuated thereby, a buckling memberactuated by the cam members and a resilient member actuated by thebuckling member for effecting eng ment of the contact members.

8. n a temperature-control system, the combination with a heat-storadevice, of a casing, a plurality of helical y-wound bimetallic membersin the casin a plurality of cam members actuated by t e bi-metallicmembers, a resilient member actuated by the cam members and a pluralityof contact members positive engagement and disengagement of which areefiected by the resilicut member.

9. In a thermostat, the combination with a plurality ofdifl'erentially-wound helical bi-metallic members, of a resilient memberactuated thereby.

10. In a thermostat, the combination with a plurality ofdifi'erentially-wound helical bi-metallic members, of a resilient memberactuated thereby and a contact member controlled by the resilientmember.

11. A thermostat comprisin a plurality of helically-woundd-ifl'erentiaIly-acting bimetallic members.

12. A thermostat comprising two helically-wound bimetallic members, theconvolutions of each being disposed between the convolutions of theother.

13. A thermostat comprising two helically-wound bimetallic membershaving the same diameter and disposed to present an apparentlycontinuous helix.

14. A thermostat comprising two helically-wound bimetallic members, theconvolutions of which are mutually interfitting.

15. A thermostat comprising two helically-wound bimetallic membersarranged to form a double interfitting helix, the elements of onebimetallic member being oppositely arranged with respect to the elementsof the other.

16. A thermostat comprising a movable contact member normall biased toengage a stationary contact mem er, means rendered operative with a snapaction for effecting the disengagement of the contact members andthermally responsive means for controlling said snap-action means.

17. A thermostat comprising a stationary contact member, a movablecontact member normally biaseds to open position relative thereto, athermally responsive means, and an operating member controllable by thethermally-responsive means under predetermined temperature conditionsand operative only under such conditions to engage and controlthe'actuation of the movable contact member.

18. In a thermostat, the combination with a movable contact member and athermally responsive device for controlling the actuation of the contactmember under predetermined thermal conditions, of means independent ofthe contact member and operative under the predetermined conditions toactuate the contact member with a quick movement.

19. In a thermostat, the combination with a movable contact member and athermally responsive device for controlling the actuation of the contactmember under predetermined thermal conditions, of energy-storing meanscontrollable by the thermally responsive member and means operative bysaid means when energized to a. predetermined degree for controlling thecontact member.

20. In a thermostat, the combination with a movable contact member and athermally responsive device for controlling the actuation of the contactmember under predetermined thermal conditions, of a snap springcontrollable by the thermally responsive member and operative whensnapped to actuate the contact member.

21. A thermostat comprising two spirally wound bimetallic membersextending in opposite directions, a supporting member to which one endof each blmetallic member is secured, contactive means so disposed as tobe relatively uninfluenced by movements of the bimetallic members withinpredetermined limits, and means controlled by the bimetallic members forcontrolling the cooperative relation between the contact members whenthe movements of the bimetallic members exceed the predetermined limits.

22. A thermostat comprising two spirally wound bimetallic membersextending in opposite directions, a supporting member to which one endof each bimetallic member is secured, a plurality of contact members andmeans controlled by the bimetallic members only when a predetermineddegree of energization therein is attained for controlling thecooperation of the contact members.

23. A thermostat comprising two spirally wound bimetallic membersextending in opposite directions which one end of each bimetallic memberis secured, a plurality of contact members and a supporting member to.

means resiliently supported by the free ends of the bimetallic membersfor controlling thecooperation of the contact members only whenpredetermined degrees of energization are attained in the bimetallicmembers.

24. A thermostat comprising two spirally wound bimetallic members, eachsupported at one end thereof, a circuit-controlling device, and meansresiliently mounted upon and controlled by the free ends of both membersfor controlling the circuit-controlling device.

25. A thermostat comprising as a unit, a supporting structure, twospirally wound bimetallic members each secured by one end thereof to thesupporting structure and extending in opposite directions, and meanssupported on and controlled by the free ends of the bimetallic membersfor controlling an external circuit.

' 26. A thermostat comprising a supporting member, two spirally woundbimetallic members having one end of each secured to the supportingmember, an element supported by the free ends of the bimetallic membersand controlled by the cumulative action of both bimetallic members, andcircuit-com trolling means rendered operative by the controlled elementwhen a predetermined torque is established by the two bimetallicmembers.

In testimony whereof, I have hereunto subscribed my name this 19th dayof December, 1919.

HORACE F. BANAN.

